001/* 002 * Copyright (C) 2007 The Guava Authors 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * http://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package com.google.common.collect; 018 019import static com.google.common.base.Preconditions.checkNotNull; 020 021import com.google.common.annotations.GwtCompatible; 022import com.google.common.annotations.GwtIncompatible; 023import java.io.IOException; 024import java.io.ObjectInputStream; 025import java.io.ObjectOutputStream; 026import java.util.Collection; 027import java.util.Comparator; 028import java.util.NavigableMap; 029import java.util.NavigableSet; 030import java.util.SortedSet; 031import java.util.TreeMap; 032import java.util.TreeSet; 033import javax.annotation.Nullable; 034 035/** 036 * Implementation of {@code Multimap} whose keys and values are ordered by 037 * their natural ordering or by supplied comparators. In all cases, this 038 * implementation uses {@link Comparable#compareTo} or {@link 039 * Comparator#compare} instead of {@link Object#equals} to determine 040 * equivalence of instances. 041 * 042 * <p><b>Warning:</b> The comparators or comparables used must be <i>consistent 043 * with equals</i> as explained by the {@link Comparable} class specification. 044 * Otherwise, the resulting multiset will violate the general contract of {@link 045 * SetMultimap}, which it is specified in terms of {@link Object#equals}. 046 * 047 * <p>The collections returned by {@code keySet} and {@code asMap} iterate 048 * through the keys according to the key comparator ordering or the natural 049 * ordering of the keys. Similarly, {@code get}, {@code removeAll}, and {@code 050 * replaceValues} return collections that iterate through the values according 051 * to the value comparator ordering or the natural ordering of the values. The 052 * collections generated by {@code entries}, {@code keys}, and {@code values} 053 * iterate across the keys according to the above key ordering, and for each 054 * key they iterate across the values according to the value ordering. 055 * 056 * <p>The multimap does not store duplicate key-value pairs. Adding a new 057 * key-value pair equal to an existing key-value pair has no effect. 058 * 059 * <p>Null keys and values are permitted (provided, of course, that the 060 * respective comparators support them). All optional multimap methods are 061 * supported, and all returned views are modifiable. 062 * 063 * <p>This class is not threadsafe when any concurrent operations update the 064 * multimap. Concurrent read operations will work correctly. To allow concurrent 065 * update operations, wrap your multimap with a call to {@link 066 * Multimaps#synchronizedSortedSetMultimap}. 067 * 068 * <p>See the Guava User Guide article on <a href= 069 * "https://github.com/google/guava/wiki/NewCollectionTypesExplained#multimap"> 070 * {@code Multimap}</a>. 071 * 072 * @author Jared Levy 073 * @author Louis Wasserman 074 * @since 2.0 075 */ 076@GwtCompatible(serializable = true, emulated = true) 077public class TreeMultimap<K, V> extends AbstractSortedKeySortedSetMultimap<K, V> { 078 private transient Comparator<? super K> keyComparator; 079 private transient Comparator<? super V> valueComparator; 080 081 /** 082 * Creates an empty {@code TreeMultimap} ordered by the natural ordering of 083 * its keys and values. 084 */ 085 public static <K extends Comparable, V extends Comparable> TreeMultimap<K, V> create() { 086 return new TreeMultimap<K, V>(Ordering.natural(), Ordering.natural()); 087 } 088 089 /** 090 * Creates an empty {@code TreeMultimap} instance using explicit comparators. 091 * Neither comparator may be null; use {@link Ordering#natural()} to specify 092 * natural order. 093 * 094 * @param keyComparator the comparator that determines the key ordering 095 * @param valueComparator the comparator that determines the value ordering 096 */ 097 public static <K, V> TreeMultimap<K, V> create( 098 Comparator<? super K> keyComparator, Comparator<? super V> valueComparator) { 099 return new TreeMultimap<K, V>(checkNotNull(keyComparator), checkNotNull(valueComparator)); 100 } 101 102 /** 103 * Constructs a {@code TreeMultimap}, ordered by the natural ordering of its 104 * keys and values, with the same mappings as the specified multimap. 105 * 106 * @param multimap the multimap whose contents are copied to this multimap 107 */ 108 public static <K extends Comparable, V extends Comparable> TreeMultimap<K, V> create( 109 Multimap<? extends K, ? extends V> multimap) { 110 return new TreeMultimap<K, V>(Ordering.natural(), Ordering.natural(), multimap); 111 } 112 113 TreeMultimap(Comparator<? super K> keyComparator, Comparator<? super V> valueComparator) { 114 super(new TreeMap<K, Collection<V>>(keyComparator)); 115 this.keyComparator = keyComparator; 116 this.valueComparator = valueComparator; 117 } 118 119 private TreeMultimap( 120 Comparator<? super K> keyComparator, 121 Comparator<? super V> valueComparator, 122 Multimap<? extends K, ? extends V> multimap) { 123 this(keyComparator, valueComparator); 124 putAll(multimap); 125 } 126 127 /** 128 * {@inheritDoc} 129 * 130 * <p>Creates an empty {@code TreeSet} for a collection of values for one key. 131 * 132 * @return a new {@code TreeSet} containing a collection of values for one 133 * key 134 */ 135 @Override 136 SortedSet<V> createCollection() { 137 return new TreeSet<V>(valueComparator); 138 } 139 140 @Override 141 Collection<V> createCollection(@Nullable K key) { 142 if (key == null) { 143 keyComparator().compare(key, key); 144 } 145 return super.createCollection(key); 146 } 147 148 /** 149 * Returns the comparator that orders the multimap keys. 150 * 151 * @deprecated Use {@code ((NavigableSet<K>) multimap.keySet()).comparator()} instead. This method 152 * is scheduled for removal in April 2019. 153 */ 154 @Deprecated 155 public Comparator<? super K> keyComparator() { 156 return keyComparator; 157 } 158 159 @Override 160 public Comparator<? super V> valueComparator() { 161 return valueComparator; 162 } 163 164 /** 165 * @since 14.0 (present with return type {@code SortedSet} since 2.0) 166 */ 167 @Override 168 @GwtIncompatible // NavigableSet 169 public NavigableSet<V> get(@Nullable K key) { 170 return (NavigableSet<V>) super.get(key); 171 } 172 173 /** 174 * {@inheritDoc} 175 * 176 * <p>Because a {@code TreeMultimap} has unique sorted keys, this method 177 * returns a {@link NavigableSet}, instead of the {@link java.util.Set} specified 178 * in the {@link Multimap} interface. 179 * 180 * @since 14.0 (present with return type {@code SortedSet} since 2.0) 181 */ 182 @Override 183 public NavigableSet<K> keySet() { 184 return (NavigableSet<K>) super.keySet(); 185 } 186 187 /** 188 * {@inheritDoc} 189 * 190 * <p>Because a {@code TreeMultimap} has unique sorted keys, this method 191 * returns a {@link NavigableMap}, instead of the {@link java.util.Map} specified 192 * in the {@link Multimap} interface. 193 * 194 * @since 14.0 (present with return type {@code SortedMap} since 2.0) 195 */ 196 @Override 197 public NavigableMap<K, Collection<V>> asMap() { 198 return (NavigableMap<K, Collection<V>>) super.asMap(); 199 } 200 201 /** 202 * @serialData key comparator, value comparator, number of distinct keys, and 203 * then for each distinct key: the key, number of values for that key, and 204 * key values 205 */ 206 @GwtIncompatible // java.io.ObjectOutputStream 207 private void writeObject(ObjectOutputStream stream) throws IOException { 208 stream.defaultWriteObject(); 209 stream.writeObject(keyComparator()); 210 stream.writeObject(valueComparator()); 211 Serialization.writeMultimap(this, stream); 212 } 213 214 @GwtIncompatible // java.io.ObjectInputStream 215 @SuppressWarnings("unchecked") // reading data stored by writeObject 216 private void readObject(ObjectInputStream stream) throws IOException, ClassNotFoundException { 217 stream.defaultReadObject(); 218 keyComparator = checkNotNull((Comparator<? super K>) stream.readObject()); 219 valueComparator = checkNotNull((Comparator<? super V>) stream.readObject()); 220 setMap(new TreeMap<K, Collection<V>>(keyComparator)); 221 Serialization.populateMultimap(this, stream); 222 } 223 224 @GwtIncompatible // not needed in emulated source 225 private static final long serialVersionUID = 0; 226}